Polymeric waterproofing membranes on the basis of ethylene-homopolymers and/or ethylene-copolymers as well as propylene-homopolymers and/or propylene-copolymers are known. See for example the products of the firm National Seal Company in Aurora, Ill 60504, USA and products of the firm Montell Polyolefins in I-44100 Ferrara, Italy.
Polymeric waterproofing membranes made of PE-HD (Polyethylene-high density) with a barrier layer of exclusively rolled aluminum foils (from about 50 to about 250 micrometer thick) are known.
Already at a small, unimportant biaxial, elongation this aluminum-barrier layer tears, and the barrier function is reduced considerably.
In the in DE OS 35 14 383, corresponding to EP 0 199 099 A2, described polymeric waterproofing membrane the inside situated layers must have--citation--at least approximative the same mechanical characteristics as those of the outside situated polymeric membranes--end of citation -.
The in DE OS 35 14 383 mentioned--citation--high elongation--end of citation--concerns a monoaxial elongation, which has nothing to do with a biaxial elongation.
For the coating of deposits and land-fills are used mainly waterproofing membranes made of PE-HD.
Polymeric membranes of this kind have a small biaxial elongation and, due to their small flexibility, they adapt themselves correspondingly bad to the sealing carrier.
When the maximum value of the biaxial elongation is trespassed, then the polymeric membrane tears. This results therein that detrimental compounds may come through the originated leakages into the water, into the ground or into the atmosphere.
Conventional waterproofing membranes on the basis of polyethylene should practically not be used for the sealing of deposits and land-fills, due to their high permeation rates, such as for example for halogenated hydrocarbons, such as dichloro benzene.